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Biomedical subjects

R H Taylor

Publications and source records attributed to R H Taylor.

142 records · Page 8Linked to original sources
PubMed1976

Comparison of human and hamster mitochondrial transfer RNA. Physical properties and methylation status.

We have compared mitochondrial transfer RNA from cultured human (HeLa) and hamster(BHK) cells, giving emphasis to distinctive properties previously noted for the BHK system. Both HeLa and BHK mitochondrial tRNA sedimented slower, and had lower mobilities in "warm" acrylamide gels, than their cytoplasmic counterparts, suggesting that both mitochondrial tRNA populations have unusually loose configurations. HeLa mitochondrial tRNA was found to contain 2.8 methyl groups per 100 nucleotides compared to 8.7 for cytoplasmic, figures similar to previous BHK results. Both mitochondrial tRNA populations were notably deficient in 7-methylguanine, methylribose, and methylated pyrimidines. We propose that mitochondrial tRNA (or perhaps animal mitochondrial tRNA) constitutes a distinct evolutionary class.

Animals↗
PubMed1975

The methylation state of poly A-containing messenger RNA from cultured hamster cells.

The poly A-containing mRNA of cultured hamster (BHK-21) cells has been examined with regard to methylation status. Steady state-labeled mRNA was obtained by incubating cells for 20-22h in the presence of [methyl-3H]-methionine and 32Pi. The degree of methylation of this RNA was 1.8 methyl groups per 1000 nucleotides, or 4-5 methyl groups on the average per molecule. The nature of the methylated residues was determined by paper chromatography and electrophoresis of acid and alkaline hydrolysates, by DEAE cellulose chromatography of alkaline hydrolysates and of T2 RNase digests, and by examining the effect of subjecting samples to "beta-elimination." Approx. half of the methyl groups occurred in standard ("internal") linkage, 10% as m5Cp and 40% as m6Ap residues. The remainder occurred at least for the most part in "blocked" 5'-termini with the presumptive structure m7G(5')ppp(Nm)p.., where Nm was Gm, m6Am, Um, or Cm.

Cell Line↗
PubMed1973

Delayed-incubation membrane-filter test for fecal coliforms.

A delayed-incubation membrane-filter technique for fecal coliforms was developed and compared with the immediate fecal coliform test described in Standard Methods for the Examination of Water and Wastewater (13th ed., 1971). Laboratory and field evaluations demonstrated that the delayed-incubation test, with the use of the proposed vitamin-free Casitone holding medium, produces fecal coliform counts which very closely approximate those from the immediate test, regardless of the source or type of fresh-water sample. Limited testing indicated that the method is not as effective when used with saline waters. The delayed-incubation membrane-filter test will be especially useful in survey monitoring or emergency situations when the standard immediate fecal coliform test cannot be performed at or near the sample site or when time and temperature limitations for water sample storage cannot be met. The procedure can also be used for analyzing the bacterial quality of water or waste discharges by a standardized procedure in a central examining laboratory remote from the sample source.

Bacteriological Techniques↗
PubMed1973

Comparison of two-point (AutoAnalyzer II) with kinetic methods for transaminase assay.

The general performance of the Technicon AutoAnalyzer II method for the routine estimation of serum aspartate and alanine transaminase has been assessed and compared with that of the LKB reaction rate analyser. The results of the two methods correlate, there is little difference in precision, and running costs are comparable. Some of the relative advantages of the two types of analysis are discussed.

Alanine Transaminase↗
PubMedDate not supplied

Prospective serial liver ultrasound scanning in resectable colorectal cancer treated with adjuvant razoxane.

Prospective serial ultrasound scanning (U/S) of the liver at 3-monthly intervals has been used to detect the presence of hepatic metastases from successfully resected Dukes' A, B and C grade colorectal carcinomas in a trial of the antimetastatic agent razoxane (ICRF 159). One hundred and twenty-six consecutive patients were randomly allocated to either adjuvant razoxane treatment (61) or to no further treatment (65). Twenty-six patients, 15 in the control group (23 per cent) and 11 in the razoxane treatment group (18 per cent) have developed hepatic metastases. All but three patients in the treated group and four in the controls were detected by U/S. In the control group four patients had definite metastases when metastases were first seen by ultrasound and three more, among the eight who initially had probable metastases, became definite metastases on ultrasound. In the treated group four patients had definite metastases and four more developed them amongst 12 who had probable metastases. The remaining eight of these 12 all regressed completely. This compared with only one complete regression (additionally on 5-FU for lung secondaries) amongst the eight controls who had probable metastases. The median time to development of liver metastases detected by U/S and other means was 59 weeks in the control group and 91 weeks in the razoxane treatment group. Ultrasound has proved to be a safe, sensitive and acceptable serial imaging technique for detecting colorectal liver metastases. Used prospectively, U/S has been valuable in monitoring the natural history of liver metastases and their behaviour during razoxane treatment.

Colonic Neoplasms↗
PubMedDate not supplied

A model for dosing gentamicin in children and adolescents that adjusts for tissue accumulation with continuous dosing.

The pharmacokinetics of gentamicin were evaluated in 50 children and adolescents during a multiple dose course of therapy. Parameters of a 2-compartment pharmacokinetic model were derived from serial serum concentrations and urinary excretion rates measured for up to 11 days following the last dose of gentamicin administered to 10 of these patients. These parameters were used to simulate changes in serum concentrations and half-lives that would occur during a standard 6-hour dosing interval with continuous dosing. The data indicated that the half-life for decline in serum concentrations after the first dose was 76 +/- 8% of the half-life at steady-state, and that the half-life after the fourth dose exceeded 90% of the steady-state half-life. These underestimations of the steady-state serum half-life were incorporated into a 1-compartment model to simulate steady-state peak and nadir serum concentrations by using pharmacokinetic parameters measured after the first dose of gentamicin administered to 40 patients. Steady-state serum concentrations predicted by the true 1-compartment model and by the adjusted model were compared with concentrations measured at steady-state. The concentrations predicted by the former model were significantly different from and consistently less than measured concentrations. Concentrations predicted by the adjusted model were not significantly different from concentrations measured at steady-state. These data indicate that the new model offers a simple and more accurate method of simulating steady-state concentrations from pharmacokinetil for individualising therapy.

Adolescent↗
PubMedDate not supplied

Effect of acarbose on the 24-hour blood glucose profile and pattern of carbohydrate absorption.

Acarbose (Bay g 5421) is a powerful alpha-glucoside hydrolase inhibitor of potential value in the treatment of diabetes and hypoglycemic dumping syndrome after gastric surgery. The extent of its use may be limited by symptoms produced by carbohydrate malabsorption. To minimize these, the action of low doses of acarbose on 24-h blood glucose profiles and hydrogen evolution have been studied on four ambulant volunteers on control diets, after exclusion of sucrose and also after addition of guar in an attempt to enhance the therapeutic effect. Replacement of dietary sucrose by starch abolished significant hydrogen evolution in the morning after low doses of acarbose but did not reduce its effectiveness in decreasing the mean three-meal blood glucose area by 41% (P less than 0.002). Addition of hydrated guar to this diet reduced the mean three-meal glucose area after acarbose further by 72% (P less than 0.001) but increased hydrogen evolution. The results suggest that acarbose will be both effective and acceptable given at low dose when the dietary carbohydrate is starch.

Acarbose↗